Method and apparatus for extruding wire



Feb. 20, 1968 A. H. HORNEN 3,

METHOD AND APPARATUS FOR EXTRUDING WIRE Filed Oct. 20, 1965 2 Sheets-Sheet 1 /0 /a Z0 Z2 Z4; 2 F /2 a2 Z 24 I If i I 3 4 I ff; /4 3 /4 I H I 4 I .am

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'ZZ Z6 36 r E \l-W TIG 3 INVENTOR ALBERT H. HORNE Arromvsys Feb. 20, 1968 A, H ORNE 3,369,574

METHOD AND APPARATUS FOR EXTRUDING WIRE Filed Oct. 20, 1965 2 Sheets-Sheet ALBERT H. HORNE it States Patent Patented Feb. 20, 1968 3,369,574 METHOD AND APPARATUS FOR EXTRUDING WIRE Albert H. Home, Mendenhail, Pa., assignor to Hoover Ball and Bearing Company, Saline, Mich, a corporation of Michigan Filed Oct. 20, 1965, Ser. No. 498,501 7 Claims. (Cl. 140-105) ABSTRACT 01* THE DISQLQSURE The manufacture of generally sinuous shape wire springs by progressively forcing straight wire pieces downwardly through a die passage shaped to progressively bend each piece in a horizontal plane. The wire pieces are arranged in a vertically extending stack in the die and each time a wire piece is added to the stack, the stack is forcibly moved through the die passage to subject each wire piece to a force causing deformation thereof so that each piece is progressively bent so that it emerges from the die in the desired final sinuous shape.

This invention relates generally to the art of shaping wire and more particularly to an improved method and apparatus for extruding straight wire so as to form Wire of a desired non'straight shapev The method and apparatus of this invention are particularly useful in the manufacture of Wire springs of the well known sinuous or formed wire shape. Heretofore such springs have been manufactured in machines utilizing a large number of moving parts which operate to bend straight wire. Such machines usually require continuous maintenance because of the large number of moving parts, and are therefore costly to keep in working condition. Furthermore, such machines must be especially built to produce springs of certain shape and have only scrap value once they become worn out because they cannot be used for other purposes. All of the above factors contribute to the cost of the wire spring products made on these machines. It is an object of this invention, therefore, to provide an improved method and apparatus for extruding wire which enables the use of conventional press equipment and the production of shaped wire products at a reduced cost.

A further object of this invention is to provide a method and apparatus for producing shaped wire products in which lengths of straight wire are fed successively into an extrusion die and progressively forced through the die which is shaped so that the straight lengths of wire are progressively subjected to forces causing small deformations in the wire and providing for the desired shape in the final wire product which emerges from the die.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims, and the accompanying drawing in which:

FIGURE 1 is a side view of the wire extrusion apparatus of this invention, showing the apparatus in a position in which it has received a length of wire in a position to be forced into the die passage;

FIGURE 2 is a side view of the wire extrusion apparatus of this invention, illustrated similarly to FIG. 1, showing the apparatus in a position immediately following the extrusion of a wire product from the die passage;

FIGURE 3 is a top view of the die in the apparatus of this invention as seen from substantially the line 33 in FIG. 1, showing the shape of the inlet end of the die passage;

FIGURE 4 is a sectional view of the apparatus of this invention looking substantially along the line 44 in FIG. 1, showing the shape of the outlet end of the die passage;

FIGURE 5 is a fragmentary front elevational view of a portion of the apparatus of this invention, with some parts of the die broken away and other parts shown in section for the purpose of clarity; and

FIGURE 6 is a fragmentary top view of a center section of an extruded wire product formed in the apparatus of this invention, illustrating the shapes through which the wire is progressively deformed from the illustrated straight shape to the desired final shape.

With reference to the drawing, the apparatus of this invention, indicated generally at 10, is illustrated in FIG. 1 as including a die member 12 mounted in a holding block 14 which is supported at its lower end on a press bed 16. A press plunger 18, disposed above the press bed 16 is provided with a head 20 shaped to force wire into the upper end of the die 12. Straight wire pieces 22 of predetermined length are fed to the upper end of the die 12 by an inclined chute 24, and an endless belt-type conveyor 26, disposed below the die 12, receives extruded wire from the die 12 and ejects this wire into a shipping container or the like indicated at 28.

As shown in FIGS. 3, 4 and 5, the die 12 is formed with a passage 30 which extends vertically therethrough and has an inlet end 32 which is in the form of a straight slot of a length to receive the straight wire pieces 22. At its outlet end 34, the passage 30 is of a shape in horizontal section (FIG. 4) corresponding to the desired shape of the final wire products 36 which are to be formed in the apparatus 10. As shown in FIGS. 3 and 6, a final product 36, in the illustrated embodiment of the invention, is of formed wire shape consisting of a plurality of torsion bars 38, only two of which are shown, and connecting wire portions 41). It is to be understood that the final wire product 36 can be of substantially any nonstraight shape, such as the shape of the Well known sinuous wire, all of which shapes, including the illustrated shape, are hereinafter sometimes referred to as substantially sinuous.

Between the inlet end 32 of the die passage 30 and the outlet end 34, the die passage 30 is shaped in horizontal section so as to provide for a progressive deformation of the straight Wire piece 22 until it is shaped to the shape of the final wire product 36. For example, adjacent the inlet opening 32, the die passage 30 is of a shape in horizontal section like the shape illustrated at 42 in FIG. 6 for a bent wire piece 22. As the passage 30 progresses from the inlet opening 32 toward the discharge opening 34, it is progressively shaped in horizontal section to correspond to the shapes indicated at 44, 46, 48, 50, 52 and 54 in FIG. 6. In horizontal section in between each of the horizontal sections at which the passage conforms to the illustrated shapes 4454, the passage 30 is of a shape in between the illustrated shapes.

In the operation of the apparatus 10, assume that the die 12 has its passage 30 free of wire, and that a straight wire piece 22 has been fed by the chute 24 to a position in which the wire piece 22 is at the inlet slot 32 for the die passage 36. The press plunger 13 is moved downwardly a distance sufiicient to move the wire piece 22 a distance corresponding substantially to the diameter of the wire piece 22 so as to force the wire piece 22 such a distance into the die passage 3d. The press plunger 18 is then raised so that the next straight wire piece 22 rolls out of the chute 24 into engagement with a stop 60 on the upper end of the die 12 located so that the wire piece 22 in engagement therewith is vertically aligned with the die passage inlet 32 and the press head 20. In this position of the wire piece 22, it holds the remaining Wire pieces 22 in the chute 24 against downward movement.

The press plunger 18 is again operated so that the. head 20 forces this next straight wire piece 22 into the die pas sage 30.

This sequence is then continuously repeated so that the press plunger 18 operates on each downward movement to force another straight wire piece 22 transversely of the length thereof into the inlet end 32 of the dieopening 30..

It can thus be seen that eventually the passage 30 will be filled from inlet end 32 to discharge end 34 with lengths of wire stacked in the passage 30. The wire 22 at the inlet end 32 will be of the straight shape illustrated in FIG. 6 and the wire at the discharge end 34 will be of the shape desired for the final wire product 36. In between the inlet opening 32 and the discharge opening 34, the wire in the passage 30 will be of the intermediate shapes illustrated in FIG. 6 at 42 54, and of further intermediate shapes in between the illustrated shapes; This progressive shaping and deformation of the straight wire pieces 22 so as to extrude the final wire products 36 from the outlet opening 34- is accomplished by the pressure applied to each wire in the passage 30 by the wire next above it each time the press head is forced into the upper end 32 of the die passage 30. In response to this pressure, each piece, of wire in the passage 30 has no place to go except into the portion of the passage 30 immediately below it which is shaped to provide or a slight deformation of the wire piece. In keeping these progressive deformations of small extent, as shown in FIG. 6, the force required to move the press plunger 18 downwardly canbe maintained within practical limits. As shown in FIG. 5, the die passage 30is of a progressively decreasing length, measured horizontally, from inlet 32 to outlet 34. This is because the wire is decreased in length, measured on a straight line from end to end, as it is bent. The passage 30 is shaped so that the wire 22 is bent inwardly toward its center 23. As a result, the center of the passage 30 follows a substantially straight line 31.

Consequently, when the next wire piece 22 is forced by the head 20 into the die inlet opening 32, after the passage 30 has been filled, a final wire product 36 of the desired shape is ejected from the opening 34 onto the conveyor 26 which, in the illustrated embodiment of the invention extends through a slot in the die holding block 14 which rests on the press bed 16 so that the conveyor 26 is immediately below the die discharge opening 34. As a result, by indexing the conveyor 26 in a timed relation with the movement of the press plunger 18, the conveyor 26 continuously receives final wire products 36 from the die passage 30 and operates to progressively eject these products 36 into the container 28.

From the above description it is seen that this invention provides an improved method and apparatus 10 for converting straight wire pieces into shaped wire products 36 utilizing a press plunger 18 and a press bed 16 which can be the normal components of a conventional press of the capacity required to force the wire 22 into the die passage 30. Such conventional press equipment is readily obtainable commercially and has ready utility outside the method and the apparatus 10 of this invention. In the event the wire forming the final product 36 is to be heat treated, this is readily accomplished by maintaining the die member 12 at the necessary temperature. It is also to be understood that while the apparatus 10 has been illustrated in connection with the extrusion of straight Wire pieces 22, it is just as useful when the initial pieces are for some reason not straight, such as if they are of one of the intermediate shapes shown in FIG. 6, just so long as all the pieces 22 are of the same predetermined shape.

It will be understood that the method and apparatus for extruding wire which are herein disclosed and described are presented for purposes of explanation and illustration and are not intended to indicate limits of the invention, the scope of which is defined by the following claims.

What is claimed is:

1. Apparatus for progressively deforming a length of 4 straight wire sons to obtain a final wire product of substantially sinuous shape comprising a die member having a shaped passage extending therethrough, said passage having an inlet end shaped to receive said length of wire for movement of said wire through said passage in a direction transverse to the length of said Wire and an outlet end shaped to conform to said substantially sinuous shape, said passage being shaped so that along the length thereof between said inlet and outlet ends said passage is gradually transformed in a direction also transverse to the length of a wire therein and perpendicular to said one direction from said straight wire to said substantially sinuous shape, means for forcing a plurality of lengths of wire successively into said passage so as to fill said passage with lengths of said wire varying progressively from said straight shape at said inlet end to said substantially sinuous shape at said outlet end so that as each subsequent length of straight wire is forced into said inlet end a final wire product is extruded from said outlet end.

2. Apparatus for extruding wire pieces of predeter? mined initial shape to form shaped wire products of a desired final non-straight shape comprising a substantially horizontal press bed, a die member having an upright shaped. passage extending therethrough, means supporting the lower end of sad die member on said bed, said passage having an upper inlet end shaped to receive said length of wire for movement of saidwire through said passage in a direction transverse to the length of said Wire and an outlet end shaped to conform to said desired final shape, said passage being shaped so that along the length thereof between said inlet and outlet ends said passage is gradually transformed in horizontal section and proceeding from top to bottom thereof from a shape corresponding to the initial shape of said Wire pieces to said desired final shape, means for continuously feeding wire pieces to said inlet end of said passage, press means for forcing said wire pieces one by one into said passage through the inlet end thereof so as to fill said passage with lengths of said wire varying progressively from said initial shape at said inlet end to said final shape at said outlet end so that as each subsequent length of wire of said initial shape is forced into said inlet end a final wire product is extruded from said outlet end.

3. Apparatus for progressively deforming a length of straight wire so as to obtain a final wire product which is bent in at least one plane transverse to the length of said wire comprising a die member having a shaped passage extending therethrough, said passage having an inlet end shaped ,to receive said length of wire for movement of said wire through said passage in a direction transverse to the length of said wire andsubstantially perpendicular to said one plane in which said wire is to be bent and an outlet end shaped to conform to said heat shape, said passage being shaped so that along the length thereof between said inlet and outlet ends said passage is gradually transformed in a direction also transverse to the length of a wire therein and perpendicular to said one direction from said straight to the shape of said final wire product, means for feeding lengths of wire one by one to said inlet end and for applying a force to each length of wire at said inlet end which is transmitted to all other lengths in said passage so as to force a plurality .of lengths of straight wire successively into said passage through the inlet end thereof so as to fill said passage with engaged lengths of said wire varying progressively from said straight shape at said.

said length of wire for movement of said Wire through said passage in a vertical direction and an outlet end shaped in a horizontal plane to conform to said bent shape, said passage being shaped so that along the length thereof between said inlet and outlet ends said passage is gradually transformed in horizontal planes from said straight to said bent shape.

5. The structure according to claim 4 in which said passage is shaped so that the center thereof in a horizontal plane follows a substantially vertical line.

6. The method of deforming pieces of straight wire to form a final wire product of substantially sinuous shape bent in one plane comprising the steps of:

(a) arranging said pieces in a stack extending in one direction;

(b) adding pieces to said stack; and

(o) forcibly moving said stack each time pieces are added thereto in a first direction transverse to the length of said wire pieces and perpendicular to said plane along a confined path shaped to provide for deformation of said Wire in a second direction transverse to the length thereof and parallel to said plane to progressively bend each piece until it is of the :shape of said final wire product.

7. The method of deforming pieces of straight wire to form non-straight pieces bent in one plane, comprising stacking and concurrently therewith forcibly moving said pieces of Wire in a first direction transverse to the length thereof and perpendicular to said plane along a confined path shaped to provide for deformation of said wire in a second direction transverse to the length thereof and parallel to said plane.

References Cited UNITED STATES PATENTS 8/1915 Shelton 72-176 3/1965 Eby 14071 

